Note: Descriptions are shown in the official language in which they were submitted.
CA 02823119 2013-08-08
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FERRITE CIRCULATOR WITH ASYMMETRIC FEATURES
BACKGROUND
[0001] Ferrite circulators have a wide variety of uses in commercial and
military,
space and terrestrial, and low and high power applications. A waveguide
circulator
may be implemented in a variety of applications, including but not limited to
low
noise amplifier (LNA) redundancy switches, T/R modules, isolators for high
power
sources, and switch matrices. One important application for such waveguide
circulators is in space, especially in satellites where extreme reliability is
essential and
where size and weight are very important. Ferrite circulators are desirable
for these
applications due to their high reliability, as there are no moving parts
required. This is
a significant advantage over mechanical switching devices. In most of the
applications
for waveguide switching and non-switching circulators, small size, low mass,
and low
insertion loss are significant qualities.
[0002] A commonly used type of waveguide circulator has three waveguide arms
arranged at 1200 and meeting in a common junction. This common junction is
loaded
with a non-reciprocal material such as ferrite. When a magnetizing field is
created in
this ferrite element, a gyromagnetic effect is created that can be used for
switching the
microwave signal from one waveguide arm to another. By reversing the direction
of
the magnetizing field, the direction of switching between the waveguide arms
is
reversed. Thus, a switching circulator is functionally equivalent to a fixed-
bias
circulator but has a selectable direction of circulation. Radio frequency (RF)
energy
can be routed with low insertion loss from one waveguide arm to either of the
two
output arms. If one of the waveguide arms is terminated in a matched load,
then the
circulator acts as an isolator, with high loss in one direction of propagation
and low
loss in the other direction.
SUMMARY
[0003] In one embodiment, a ferrite element for a circulator is provided. The
ferrite
element comprises a first segment extending in a first direction from a center
portion
of the ferrite element; a second segment extending in a second direction from
the
center portion of the ferrite element; and a third segment extending in a
third direction
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from the center portion of the ferrite element Each of the first segment, the
second
segment, and the third segment has a respective width and include a channel
located
at a respective distance from a center point of the ferrite element. At least
one of the
respective width of each segment or the respective distance from the center
point for
the channel in each segment is different for each respective segment such that
the first
segment operates over a first frequency sub-band, the second segment operates
over a
second frequency sub-band, and the third segment operates over a third
frequency
sub-band.
DRAWINGS
[0004] Understanding that the drawings depict only exemplary embodiments and
are
not therefore to be considered limiting in scope, the exemplary embodiments
will be
described with additional specificity and detail through the use of the
accompanying
drawings, in which:
[0005] Figure 1 is a top view of one embodiment of an exemplary ferrite
element
having asymmetric features.
[0006] Figure 2 is a top view of another embodiment of an exemplary ferrite
element
having asymmetric features.
[0007] Figure 3A is a top view of one embodiment of an exemplary circulator
with
asymmetric features.
[0008] Figure 3B is a perspective view of one embodiment of the exemplary
circulator in Figure 3A.
[0009] Figure 4 is a high level block diagram of one embodiment of a system
having
a circulator with asymmetric features.
[0010] Figure 5A is a graph representing exemplary insertion loss data for an
exemplary embodiment of a circulator having asymmetric features.
[0011] Figure 5B is a graph representing exemplary isolation data for an
exemplary
embodiment of a circulator having asymmetric features.
[0012] Figure 5C is a graph representing exemplary return loss data for an
exemplary
embodiment of a circulator having asymmetric features.
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100131 In accordance with common practice, the various described features are
not
drawn to scale but are drawn to emphasize specific features relevant to the
exemplary
embodiments.
DETAILED DESCRIPTION
10014] In the following detailed description, reference is made to the
accompanying
drawings that form a part hereof, and in which is shown by way of illustration
specific
illustrative embodiments. However, it is to be understood that other
embodiments
may be utilized and that logical, mechanical, and electrical changes may be
made.
The following detailed description is, therefore, not to be taken in a
limiting sense.
100151 Figure 1 is a cross-sectional top view of one embodiment of an
exemplary
asymmetric ferrite element 101 used in a circulator. Ferrite element 101
includes 3
legs or segments 102-1, 102-2, and 102-3, each of which extends out from a
center
portion 107 at approximately 1200 angles from one another. Each segment 102
has a
length 114 and a width 116. The length 114 and width 116 of each leg 102 are
approximately equal to the length 114 and width 116 of the other legs 102 in
the
embodiment of Figure 1. In addition, each segment 102 includes a respective
channel
106. As used herein, the terms "channel", "aperture", and "hole" can be used
interchangeably. Each channel 106 begins at a first side 118 of the respective
segment
102 and ends at a second side 120 of the respective segment 102. The second
side
120 is opposite the first side 118. Hence, each channel 106 extends through
the width
116 of the respective segment 102 in a direction that is approximately
perpendicular
to the first side 118 and the second side 120.
10016] The channel 106-1 in leg 102-1 is located a distance L1 from a center
point
104. The channel 106-2 in leg 102-2 is located a distance L2 from the center
point
104. The channel 106-3 in leg 103-3 is located a distance L3 from the center
point
104. The distance L2 is greater than the distance L1. The distance L1 is
greater than
the distance L3. Each of the respective channels 106 can be created by boring
a hole
through the respective leg 102 of the ferrite element 101, for example. If a
magnetizing winding (also referred to herein as a wire) is inserted through
each of the
respective apertures 106, then a magnetizing field may be established in the
ferrite
element 101 by applying a current pulse to one of the magnetizing windings.
For
example, in some embodiments, the pulse length is on the order of 100
nanoseconds
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wide and 4-12 amps at its peak through the wire. The pulse latches the ferrite
element
101 into a certain magnetization and then stops. Thus, current does not have
to be
continually applied to the selected wire.
[0017] In the example shown in Figure 1, a wire 110 is inserted through the
channels
106 in each leg 102. The respective diameter of the channels 106 is determined
based
on the diameter of the wire 110 placed through the respective channels 106. In
particular, the respective diameter of the channels 106 is greater than the
diameter of
the wire 110 such that the wire 110 can be inserted through the respective
channels
106. The polarity of the magnetizing field may be switched, alternately, by
switching
the polarity of the current applied to the wire 110 to thereby provide a
switchable
circulator. However, it is to be understood that, in some embodiments, the
polarity is
not switched to provide a fixed circulator. A fixed circulator can be
connected, for
example, to a single antenna to allow both receive (Rx) and transmit (Tx)
transmission through the single antenna. Alternatively, a switching circulator
can be
used, in some embodiments, for both Rx and Tx transmission and for switching
between multiple antennas in switched beam antenna applications.
[0018] The length L1 to the channel 106-1 is measured from the center point
104 to
approximately a midpoint of the channel 106-1. Similarly, the length L2 to the
channel 106-2 and the length L3 to the channel 106-3 are each measured from
the
center point 104 to approximately a midpoint of the respective channels 106-2
and
106-3. The length from the center point 104 to the respective channel 106
influences
the operating frequency of the switchable circulator in which the ferrite
element 101
is implemented. In particular, the volume of the resonant section of the
ferrite
element 101 determines the frequency of operation to the first order. The
resonant
section of the ferrite element 101 includes the center portion 107 and the
portion of
each leg 102 between the center portion 107 of the Y-shaped ferrite element
101 and
the location of the wire 110 carrying a current pulse. The sections of the
ferrite
element in the area outside of the resonant section volume may act as return
paths for
the bias fields in the resonant section and as impedance transformers out of
the
resonant section
[0019] By using asymmetric distances L1, L2, and L3, between the center point
104
and the respective channel 106, each leg 102 of the ferrite element 101 is
configured
to operate over a different frequency sub-band. In particular, as discussed
above, the
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volume of the resonant section determines the operating frequency band to the
first
order. Since the distance from the center point 104 to each respective channel
106 is
different, the volume of the resonant section is different for each leg 102.
That is, the
first leg is associated with a first resonant section volume, the second leg
is associated
with a second resonant section volume, and the third leg is associated with a
third
resonant section volume.
[0020] In the example of Figure 1, the distance L2 is the greatest. Since the
operating
frequency band is inversely related to the volume of the resonant section, leg
102-2
operates a lower frequency sub-band than legs 102-1 and 102-3. Similarly,
since the
distance L3 is the smallest, leg 102-3 operates at a higher frequency sub-band
than
legs 102-1 and 102-2. In some embodiments, the different frequency sub-bands
are
used for both RX and Tx transmission through a single antenna. Alternatively,
in
other embodiments, one sub-band is used for Rx and a second sub-band is used
for
Tx.
[0021] In the example of Figure 1, the asymmetry in the ferrite element is
achieved
through different distances Ll, L2, and L3 between the center point 104 and
the
respective channel 106 of each leg 102. That is, the respective resonant
section
volumes are defined, at least in part, by the respective distances to the
channel 106 of
each leg 102. In other embodiments, the asymmetry is achieved through varying
the
shape of each respective leg. For example, the width of each leg can vary. In
such
embodiments, the respective width of each leg defines, at least in part, the
respective
resonant section volume.
[0022] In the example of Figure 2, each leg 202 has the same length 214, but a
different respective width 216. In particular, in the example in Figure 2, leg
202-2 has
a width 216-2 which is greater than the widths 216-1 and 216-3. Leg 202-3 in
this
example has a width 216-3 which is smaller than the widths 216-1 and 216-2.
Since
the distance L4 between the center point 204 and the respective channel 206 is
the
same for each leg 202, the volume of the resonant section for each leg 202 is
determined by the respective width 216 of each leg 202 and the volume of the
center
portion 207. Therefore, in the exemplary embodiment of Figure 2, leg 202-2
operates
at a lower frequency sub-band than legs 202-1 and 202-3 because it has the
greatest
volume. Similarly, leg 202-3 operates at a higher frequency sub-band than legs
202-1
and 202-2 because it has the smallest width 216-3.
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[0023] As discussed above, a current pulse can be applied to wire 210 to latch
the
ferrite element 201 into a certain magnetization. The pulse then stops and
does not
need to be applied continuously. A current pulse having an opposite polarity
can be
applied to the wire 210 to provide a switchable circulator. Alternatively, a
fixed
circulator can be provided by not switching the polarity of pulses applied to
the wire
210.
[0024] Figure 3A is a top view of an exemplary asymmetric circulator 300 and
Figure
3B is an isometric view of the exemplary asymmetric circulator 300. The
asymmetric
circulator 300 includes a waveguide structure 303 which defines a plurality of
waveguide arms 332 that meet in a shared junction and are generally air-
filled. For the
purposes of this description, the terms "air-filled," "empty," "vacuum-
filled," or
"unloaded" may be used interchangeably to describe a waveguide structure. The
arms
332 are arranged at approximately 120 degree angles from each other in this
example.
The conductive waveguide structure 303 may also include waveguide input/output
ports 326-1...326-3. The ports 326 can be used to provide interfaces, such as
for
signal input and output, for example.
[0025] The asymmetric circulator 300 also includes a ferrite element 301
disposed in
the air-filled waveguide structure 303, as shown in Figures 3A and 3B.
Additionally,
a dielectric spacer 320 is disposed on a top surface of ferrite element 301
and a
dielectric spacer 328 is disposed on a bottom surface of the ferrite element
301. The
materials selected for the respective spacers 320 and 328 can be chosen
independently
in terms of microwave and thermal properties to allow for more flexibility in
the
impedance matching of the circulator 300. The diameter of the spacers 320 and
328
are selected for impedance matching purposes. Although spacers 320 and 328 are
shown in Figures 3A and 3B as having a circular shape, any geometry may be
used
for the spacers 320 and 328. In addition, in some embodiments, one or more
empirical matching elements 330 can be optionally included on a conductive
portion
of the waveguide structure 303. The waveguide structure 303 can be comprised
of
any conductive material, such as, but not limited to, aluminum, silver plated
metal, or
gold plated metal. The matching elements 330 can be capacitive/inductive
dielectric
or metallic buttons that are used to empirically improve the impedance match
over the
desired operating frequency sub-band.
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[0026] In addition, in the example of Figure 3, the asymmetric circulator 300
includes
a respective dielectric transformer 322 coupled to an end of each leg 302 of
the ferrite
element 301 for purposes of impedance matching the ferrite element to the
waveguide
interface. The dielectric transformers 322 are typically used to match the
lower
impedance of the ferrite element to the higher impedance of the air-filled
waveguide
so as to reduce loss. In particular, in this embodiment, the shape of each
respective
dielectric transformer 322 is different to provide the desired impedance
matching for
each different operating sub-band. For example, in this embodiment, the
dielectric
transformer 322-2 is shorter and narrower than the dielectric transformers 322-
1 and
322-3, whereas dielectric transformer 322-1 is wider than the dielectric
transformers
322-2 and 322-3.
[0027] It is to be understood that the dimensions of each dielectric
transformer 322
vary based on the desired impedance matching for the specific implementation.
For
example, the width, height, length, number of steps in the dielectric
transformers, and
location of the steps in the transformers 322 can vary to thus achieve the
desired
impedance matching of the ferrite element 301 to the corresponding waveguide
port
326. Additionally, in other embodiments, steps in the height or width of the
waveguide arms 332 can be used in addition to or in lieu of variances in the
dimensions of the transformers 322 to achieve the desired impedance matching.
[0028] The ferrite element 301 also includes a respective channel 306 in each
of the
legs 302. In particular, in this example, the location of each channel 306 in
the
respective leg 302 differs as described above in the exemplary ferrite element
101 of
Figure 1. Thus, asymmetry in the frequency sub-band of each leg 302 is
achieved
through the different distances between a center point of the ferrite element
and the
location of the respective channel 306. However, it is to be understood that
in other
embodiments, a ferrite element similar to ferrite element 201 can be
implemented in a
circulator, such as circulator 300, to provide an asymmetric circulator having
different
operating frequency sub-bands for each leg.
[0029] A magnetizing winding 310 is inserted through the channel 306 in each
leg
302. A current pulse is applied to the wire 310 to latch the ferrite element
into a
certain magnetization, as discussed above. Additionally, a switchable
circulator can
be implemented by switching the polarity of the current pulse applied to the
magnetizing winding 310. In particular, by switching the polarity of the
current pulse,
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the signal flow direction can be switched. For example, for a first polarity
of the
current pulse, a first signal flow configuration in the asymmetric three-port
circulator
300 is 326-1-4326-2, 326-2-4326-3, and 326-3-626-1. That is a signal input via
port 326-1 is output via port 326-2; a signal input via port 326-2 is output
via port
326-3; and a signal input via 326-3 is output via port 326-1. For a second
polarity of
the current pulse, a second signal flow configuration in the asymmetric
circulator 300
is 326-1-626-3, 326-3-626-2, and 326-2-626-1.
[0030] In an ideal configuration, no portion of the input signals should
result on the
isolated port. The isolated port is the port over which the signal is not
intended to be
output. For example, if a signal is input on port 326-1, the output port in
the first
signal flow configuration described above is port 326-2 and the isolated port
is 326-3.
Hence, ideally no signal should result on port 326-3 in such a configuration.
Any loss
in signal from the input port to the output port is referred to as the
insertion loss.
Signal transferred from the input port to the isolated port is referred to as
isolation.
[0031] It is typically desirable to configure the circulator 300 to decrease
the insertion
loss and increase the isolation. For example, in one embodiment, the
circulator is
configured to have a few tenths of a dB insertion loss and approximately 20 dB
isolation. Figures 5A-5C are graphs representing exemplary simulated insertion
loss,
isolation, and return loss data for an exemplary embodiment of the asymmetric
circulator having different operation frequency sub-bands for each leg.
However, it is
to be understood that actual measurements of insertion loss, isolation, and
return loss
data will vary based on the specific implementation. In Figure 5A, the label
S21
refers to a signal traveling from a first port, such as port 326-1, to a
second port, such
as port 326-2. The label S32 refers to a signal traveling from the second port
to a
third port, such as port 326-3. The label S13 refers to a signal traveling
from the third
port to the first port. Similarly, in Figure 5B, the label S23 refers to a
signal traveling
from the third port to the second port; the label S12 refers to a signal
traveling from
the second port to the first port; and the label S31 refers to a signal
traveling from the
first port to the third port.
100321 In one example of a fixed circulator using the first signal flow
configuration, a
receiver can be coupled to the port 326-2, a transmitter can be coupled to the
port
326-3 and a single antenna can be coupled to the port 326-1. Thus, signals
received at
the antenna over a first frequency sub-band are provided to the receiver via
port 326-2
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and signals in a second frequency sub-band from the transmitter coupled to
port 326-3
are provided to the antenna via port 326-1.
[0033] In other embodiments implementing an asymmetric switchable circulator,
the
second current pulse with a second polarity is applied to the wire 310. In one
embodiment of an asymmetric switchable circulator, for example, a first
transmitter
configured to operate over a first frequency sub-band is coupled to port 326-2
and a
second transmitter configured to operate over a second frequency sub-band is
coupled
to port 326-3. Thus, in the first signal flow configuration, signals from the
second
transmitter are transmitted over an antenna coupled to the port 326-1. In the
second
signal flow configuration, signals from the first transmitter are transmitted
over the
antenna coupled to the port 326-1. Thus, the asymmetric circulator 300 can be
implemented in various systems.
[0034] For example, Figure 4 is a high level block diagram of one embodiment
of an
exemplary system 405 which implements an asymmetric circulator 400, such as
circulator 300 discussed above. System 405 can be implemented as any radio
frequency (RF) system such as, but not limited to, radar systems, satellite
communication systems, and terrestrial communications networks. The asymmetric
circulator 400 includes a ferrite element in which the volume of the resonant
section is
different for each leg of the circulator. For example, the volume can be
changed by
locating a respective channel in each leg at a different length as described
above with
respect to Figure 1. Alternatively the volume of the resonant section can be
changed
for each leg by configuring each leg with a different width as discussed above
with
respect to Figure 2. Thus, the asymmetric circulator 400 includes different
respective
operating frequency sub-bands for each leg.
[0035] The system 405 also includes a controller circuit 402 which is
configured to
provide a current pulse to a wire running through a channel in each leg as
described
above. Coupled to each port 426 is an RF component 434. Each RF component 434
can be implemented as one of a transmitter, a receiver, an antenna, or other
load
known to one of skill in the art. For example, in one embodiment, RF component
434-1 is implemented as an antenna, RF component 434-2 is implemented as a
receiver, and RF component 434-3 is implemented as a transmitter. The
asymmetric
=
circulator 400 is configured, in such an embodiment, so that signals from the
transmitter 434-3 are isolated from the receiver 434-2, but are passed through
to the
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antenna 434-1 for transmission. Similarly, signals received via antenna 434-1
are
isolated from the transmitter 434-3 and passed through to the receiver 434-2
in such
an example embodiment. However, it is to be understood that, in other
embodiments,
the RF components 434 are implemented differently than in this exemplary
embodiment. Hence, through the use of the asymmetric circulator 400, the
system
405 is able to support different frequency sub-bands on each port.
EXAMPLE EMBODIMENTS
[0036] Example 1 includes a ferrite element for a circulator, the ferrite
element
comprising a first segment extending in a first direction from a center
portion of the
ferrite element; a second segment extending in a second direction from the
center
portion of the ferrite element; and a third segment extending in a third
direction from
the center portion of the ferrite element; wherein each of the first segment,
the second
segment, and the third segment has a respective width and include a channel
located
at a respective distance from a center point of the ferrite element; wherein
at least one
of the respective width of each segment or the respective distance from the
center
point for the channel in each segment is different for each respective segment
such
that the first segment operates over a first frequency sub-band, the second
segment
operates over a second frequency sub-band, and the third segment operates over
a
third frequency sub-band.
[0037] Example 2 includes the ferrite element of Example 1, wherein the
respective
distance from the center point for the channel is the same for each respective
segment
and; wherein the width of each respective segment is different from the
respective
width of the other segments.
[0038] Example 3 includes the ferrite element of Example 1, wherein the
respective
width of each segment is the same as the width of the other segments; and
wherein the
respective distance from the center point to the respective channel in each
segment is
different for each of the first, second, and third segments.
[0039] Example 4 includes the ferrite element of Example 1, wherein the
respective
distance from the center point to the respective channel in each segment is
different
for each of the first, second, and third segments; and wherein the width of
each
respective segment is different from the respective width of the other
segments.
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[0040] Example 5 includes the ferrite element of any of Examples 1-4, wherein
the
first segment, the second segment, and the third segment are arranged at
approximately 120 degree angles from one another.
[0041] Example 6 includes a circulator comprising a waveguide having three
ports; a
ferrite element having three segments that each extend from a center portion,
the
ferrite element having a first resonant section volume associated with a first
segment,
a second resonant section volume, associated with a second segment, and a
third
resonant section volume associated with a third segment; and a magnetizing
winding
disposed in a respective channel located in each of the three segments;
wherein the
second resonant section volume is different from the first resonant section
volume and
the third resonant section volume is different from the first and second
resonant
section volumes such that the first segment operates over a first frequency
sub-band,
the second segment operates over a second frequency sub-band, and the third
segment
operates over a third frequency sub-band.
[0042] Example 7 includes the circulator of Example 6, wherein the first
segment has
a first width that defines, at least in part, the first resonant section
volume; wherein
the second segment has a second width, different from the first width, that
defines, at
least in part, the second resonant section volume; and wherein the third
segment has a
third width, different from the first width and the second width, that
defines, at least in
part, the third resonant section volume.
[0043] Example 8 includes the circulator of Example 6, wherein the channel in
the
first segment is located at a first distance from a center point of the
ferrite element, the
first distance defining, at least in part, the first resonant section volume;
wherein the
channel in the second segment is located at a second distance from the center
point of
the ferrite element, the second distance being different from the first
distance and
defining, at least in part, the second resonant section volume; and wherein
the channel
in the third segment is located at a third distance from the center point of
the ferrite
element, the third distance being different from the first distance and the
second
distance; wherein the third distance defines, at least in part, the third
resonant section
volume.
[0044] Example 9 includes the circulator of Example 6, wherein the first
segment has
a first width and the respective channel in the first segment is located at a
first
distance from a center point of the ferrite element, the first width and the
first distance
defining, at least in part, the first resonant section volume; wherein the
second
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segment has a second width, different from the first width, and the respective
channel
in the second segment is located at a second distance from the center point of
the
ferrite element, the second distance being different from the first distance;
wherein the
second width and the second distance define, at least in part, the second
resonant
section volume; wherein the third segment has a third width, different from
the first
width and the second width, and the respective channel in the third segment is
located
at a third distance from the center point of the ferrite element, the third
distance being
different from the first distance and the second distance; wherein the third
width and
the third distance define, at least in part, the third resonant section
volume.
[0045] Example 10 includes the circulator of any of Examples 6-9, further
comprising
a dielectric spacer disposed on at least one of a top surface of the ferrite
element or a
bottom surface of the ferrite element.
[0046] Example 11 includes the circulator of any of Examples 6-10, further
comprising a respective dielectric transformer coupled to an end of each of
the three
segments of the ferrite element.
[0047] Example 12 includes the circulator of any of Examples 6-11, wherein the
waveguide structure defines three arms that are arranged at approximately 120
degree
angles from one another and meet at a common junction, each arm corresponding
to
one of the three ports.
[0048] Example 13 includes the circulator of any of Examples 6-12, wherein the
three
segments of the ferrite element are arranged at approximately 120 degree
angles from
one another.
[0049] Example 14 includes the circulator of any of Examples 6-13, further
comprising one or more empirical impedance matching elements disposed on a
conductive portion of the waveguide.
[0050] Example 15 includes a system comprising a circulator comprising a
waveguide structure having three ports; a ferrite element disposed in the
waveguide
structure and comprising three segments that each extend from a center
portion; and a
wire disposed in a respective channel located in each of the three segments;
wherein
the ferrite element has a first resonant section volume associated with a
first segment,
a different second resonant section volume associated with a second segment,
and a
different third resonant section volume associated with a third segment such
that the
first segment operates over a first frequency sub-band, the second segment
operates
over a second frequency sub-band, and the third segment operates over a third
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frequency sub-band; the system further comprising a controller circuit coupled
to the
wire and configured to selectively apply a current pulse to the wire; and at
least one
radio frequency (RF) component coupled to a respective one of the ports in the
waveguide structure.
[0051] Example 16 includes the system of Example 15, wherein the first segment
of
the ferrite element has a first width that defines, at least in part, the
first resonant
section volume; wherein the second segment of the ferrite element has a second
width, different from the first width, that defines, at least in part, the
second resonant
section volume; and wherein the third segment of the ferrite element has a
third width,
different from the first width and the second width, that defines, at least in
part, the
third resonant section volume.
[0052] Example 17 includes the system of Example 15, wherein the respective
channel in the first segment is located at a first distance from a center
point of the
ferrite element, the first distance defining, at least in part, the first
resonant section
volume; wherein the respective channel in the second segment is located at a
second
distance from the center point of the ferrite element, the second distance
being
different from the first distance and defining, at least in part, the second
resonant
section volume; and wherein the respective channel in the third segment is
located at a
third distance from the center point of the ferrite element, the third
distance being
different from the first distance and the second distance; wherein the third
distance
defines, at least in part, the third resonant section volume.
[0053] Example 18 includes the system of Example 15, wherein the first segment
of
the ferrite element has a first width and the respective channel in the first
segment is
located at a first distance from a center point of the ferrite element, the
first width and
the first distance defining, at least in part, the first resonant section
volume; wherein
the second segment of the ferrite element has a second width, different from
the first
width, and the respective channel in the second segment is located at a second
distance from the center point of the ferrite element, the second distance
being
different from the first distance; wherein the second width and the second
distance
define, at least in part, the second resonant section volume; wherein the
third segment
of the ferrite element has a third width, different from the first width and
the second
width, and the respective channel in the third segment is located at a third
distance
from the center point of the ferrite element, the third distance being
different from the
13
CA 02823119 2013-08-08
first distance and the second distance; wherein the third width and the third
distance
define, at least in part, the third resonant section volume.
[0054] Example 19 includes the system of any of Examples 15-18, wherein the
waveguide structure defines three arms that are arranged at approximately 120
degree
angles from one another and meet at a common junction, each arm corresponding
to
one of the three ports.
[0055] Example 20 includes the system of any of Examples 15-19, wherein the
three
segments of the ferrite element are arranged at approximately 120 degree
angles from
one another.
[0056] Although specific embodiments have been illustrated and described
herein, it
will be appreciated by those of ordinary skill in the art that any
arrangement, which is
calculated to achieve the same purpose, may be substituted for the specific
embodiments shown. Therefore, it is manifestly intended that this invention be
limited only by the claims and the equivalents thereof.
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